Immunogen sequence: VSTIQVEWPE PDLAPAIKYY SDGQHRPPPA QHRKPKPKPK VGFPM Antigen sequence identity: Mouse 67%; Rat 71%. CLDN23 is a four-transmembrane protein with WWCC motif, defined by W-X(17-22)-W-X(2)-C-X(8-10)-C. It is a candidate tumor suppressor gene